1. Field of the Invention
The present invention relates to a method for treating bio-oil collected from coconut husk produced during palm oil press, etc.
2. Description of the Related Art
Palm oil, which is used as a raw material for soap, glycerin, napalm bomb, etc., can be obtained from the fruits of “oil palm” growing in Malaysia, Indonesia, etc. Palm oil can also be used as rolling oil during the production steps of steel plates. On the other hand, coconut husk, which was conventionally disposed after palm oil press, is still rich in oil components. Noting this fact, production of new fuel oil from the coconut husk is attempted although the oil generates slightly lower calorie. For example, oil components are obtained by crushing coconut husk from which oil has been pressed out, vaporizing the oil components by contacting them with particles such as sands heated to high temperature, and condensing the gas using a water-cooling condenser. Besides coconut husk, cereal such as sugarcane, corn, etc. can be used as a raw material. Hereinafter the thus-obtained oil having low purity is referred to as “bio-oil”. Organisms such as plants are sometimes considered to be an energy source and referred to as “biomass”, and “bio-oil” is synonymous to “biomass oil”.
The characteristics of bio-oil obtained from coconut husk raw material are compared to those of heavy oil A, heavy oil C and light oil, and are shown in Table 1.
TABLE 1Heavy oil AHeavy oil CLight oilBio-oilReactionneutralneutralneutralacidicCalorie45,20044,00046,00016,190[kJ/kg]Water content0.10.10.131.9[%]
The calories of heavy oil A and heavy oil C are each approximately 45,000 kJ/kg, whereas that obtained from bio-oil is approximately 30% (16,190 kJ/kg). In this connection, the calorie originally generated by palm oil is 39,000 kJ/kg (not shown in Table 1).
As is apparent from Table 1, heavy oils and light oil contain little amount of water, whereas bio-oil contains approximately 30% of water. Furthermore, conventional heavy oil is neutral, whereas bio-oil is weak acidic and has a pH of 3.5. This is presumed to be due to acetic acid contained in the bio-oil by the amount of approximately 15%. Furthermore, significant lower calorie of bio-oil than that of heavy oil can be considered to be due to water and acetic acid.
Such acidic bio-oil cannot be practically used for fuel in industry because it causes heavy corrosion of piping, reservoir tanks, etc. On the other hand, when conventional method of neutralization using calcium hydroxide or caustic soda is carried out, calorie of the bio-oil is further decreased and such bio-oil cannot be used as fuel.